alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE TrustConnect RAT CnC Activity (Agent Registration)"; flow:established,to_server; flowbits:set,ET.TrustConnect.Reg; http.method; content:"POST"; http.uri; bsize:19; content:"/api/agent/register"; fast_pattern; http.header_names; content:!"|0d 0a|referer|0d 0a|"; nocase; content:!"|0d 0a|x-"; nocase; http.request_body; content:"|7b 22|installToken|22 3a 22|"; startswith; threshold:type limit,count 1,seconds 300,track by_src; reference:url,proofpoint.com/us/blog/threat-insight/dont-trustconnect-its-a-rat; classtype:command-and-control; sid:2067879; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, tls_state TLSDecrypt, created_at 2026_02_23, deployment Perimeter, deployment SSLDecrypt, malware_family TrustConnect, confidence High, signature_severity Critical, updated_at 2026_02_23; target:src_ip;)